(Try accessing the Annapolis City Directory if you want to get an idea of how clumsy this site can be....whoops...I said I was done whining, didn't I?)
An easy to overlook resource are the Maryland State Archives Indices, which include some of the best family history lookup tools the state has to offer. There is a lot of genealogical information scattered about:
Some good general history collections:
Photographic Archives of Maryland, which, amazingly, have no photos of onetime Governor Spiro Agnew, though I managed to find one with the sitewide search funtion.
Maryland State Archives Map Collections
African American Research at The Maryland State Archives. There's a lot here, including slave censuses, and Civil War colored troop rolls.
Web Publications of the Maryland State Archives, a list of various collections that seemingly focus on online content.
Teaching American History in Maryland, bringing historical resource materials and professional-development experiences to K-12 U.S. history teachers.
A variety of On-Line Exhibits, including the Maryland Women's Hall of Fame.
The official State Archives aren't the only game in town. The Maryland Historical Society also has some excellent online collections:
There's also the Maryland Historical Trust's Maryland Inventory of Historic Properties.
By the way, here's the homepage of the Maryland State Archives (as distinct from their online collections).
More historical archives and research materials can be found at these excellent resources: